WO2022027962A1

WO2022027962A1 - Combined metal powder magnetic core and inductance device formed by same

Info

Publication number: WO2022027962A1
Application number: PCT/CN2021/079712
Authority: WO
Inventors: 肖俊承; 王一龙; 邵革良
Original assignee: 广东伊戈尔智能电器有限公司; 佛山市顺德区伊戈尔电力科技有限公司
Priority date: 2020-08-05
Filing date: 2021-03-09
Publication date: 2022-02-10
Also published as: CN111785490A; US20220392686A1

Abstract

A combined metal powder magnetic core and an inductance device formed by same. The combined metal powder magnetic core comprises an upper magnet yoke, a lower magnet yoke, and core columns arranged between the upper magnet yoke and the lower magnet yoke; the combined metal powder magnetic core is characterized in that the upper magnet yoke and the lower magnet yoke are respectively C-shaped, two end parts of the upper magnet yoke and the lower magnet yoke are respectively butted with the two core columns to form a magnetic circuit, an air gap is arranged at the butted position between the upper magnet yoke and the lower magnet yoke, and the distance between central areas of the air gap is smaller than that between peripheral positions. Compared with the prior art, the magnet yokes are C-shaped, so that the magnetic flux leakage at shoulder parts of the magnet yokes can be greatly reduced, thereby reducing magnetic loss; then, as the distance between the peripheral positions of the air gap is increased, magnetic resistance of the central areas of the air gap is far smaller than that of the peripheral positions, so that a magnetic field is close to the central areas to reduce magnetic flux leakage, and eddy current caused by magnetic flux leakage to peripheral copper wires is reduced.

Description

Combined metal powder magnetic core and formed inductance device

technical field

The present invention relates to a combined metal powder magnetic core and the formed inductive device.

Background technique

The invention patent with application number 201880024695.3 and titled "Reactor" proposes a solution to two problems, the first problem is to set the core blocks 3A, 3B to be formed from a formed body of a composite material containing magnetic powder and resin Since the composite material molded body has resin interposed between the powder particles of the magnetic powder, the relative magnetic permeability can be lowered. Therefore, when the core blocks 3A and 3B constituting the magnetic core 3 are composite material molded bodies, It is not necessary to provide an interval for adjusting the inductance of the reactor 1 in the magnetic core 3 (for example, between the core blocks 3A and 3B), or even if the interval is provided, the interval may be small. Thereby, leakage magnetic flux hardly occurs in the magnetic core 3 (inner core portion 31 ), and the gap 34 between the inner peripheral surface of the winding portion 2 c and the outer peripheral surface of the inner core portion 31 can be reduced. That is to say, by improving the material properties of the formed body of the composite material, the gap between the magnetic cores can be small or not so as to improve the leakage flux problem; the second problem is that it is disclosed that the corners 313 of the inner core 31 are Chamfered structure. By chamfering the corners 313 of the inner core portion 31 and increasing the gaps 34 at the corners 313 , the resin flow path (flow path cross-sectional area) is easily secured, and the formation of the inner resin portion 41 is facilitated. The corners 313 of the inner core portion 31 make it difficult for the magnetic flux to flow and function as an effective magnetic circuit, so the influence on the effective magnetic circuit is relatively small. Therefore, since the corners 313 of the inner core portion 31 are chamfered, the flow path of the resin can be secured and the reduction of the effective magnetic path cross-sectional area can be effectively suppressed. That is to say, by chamfering the corners 313 to improve the magnetic flux on the magnetic circuit path of the core body, it is difficult to flow. difficult to form.

For applications such as vehicle boost inductors, photovoltaic inverter inductors, and charging pile PFC inductors that operate at high current, high power, and high power density, these inductors are objectively required to have a very high inductance current product factor L*I. Prevent the problem caused by the sharp drop of inductance under high current working conditions. In order to realize the design of this type of power inductor, the magnetic core material of this type of inductor generally adopts the solutions disclosed in the above-mentioned prior art and adopts the metal powder magnetic core design with relatively low magnetic permeability (μr: 20~200). However, in order to improve its ability to use large currents, a certain number of millimeters of non-magnetic conductive space must be intentionally introduced at the splicing of the magnetic core as the magnetic core air gap. However, substances in the so-called non-magnetic space, such as air, do not completely block the magnetic field in the air gap of the magnetic core. These substances have a relative magnetic permeability of 1 because their relative magnetic permeability μr is close to the vacuum, which is lower than that of the combined magnetic core. In the case of magnetic permeability, these so-called non-magnetic materials and even vacuum spaces, although the magnetoresistance is large, still become an important magnetic flux shunting ability. This phenomenon is often explained as magnetic leakage. Under the excitation of high frequency and high current, a large part of the leakage magnetic flux of the non-magnetic material at the air gap of these magnetic cores or the alternating magnetic flux circulating in the space will directly penetrate the copper wire surface of the surrounding winding coils. In the high current application of coil winding, the shape of the winding copper wire is thick, which will cause serious eddy current loss on the coil.

technical solutions

In order to significantly improve the influence of the large air gap caused by the application of high current and high power density, and then lead to a large amount of leakage magnetic flux around the air gap penetrating the eddy current formed by the surface of the copper wire, the present invention first proposes a method by modifying the magnetic core of the magnetic core. A solution for the shape of the magnetic core at the road splicing, the combined metal powder magnetic core includes upper and lower magnetic yokes and a core column arranged between the upper and lower magnetic yokes; it is characterized in that the upper and lower magnetic yokes The yokes are C-shaped respectively, the two ends of the upper and lower magnetic yokes are respectively butted with the two core columns to form a magnetic circuit, and an air gap is arranged at the butting position between them, and the distance between the central areas of the air gaps The spacing is smaller than the surrounding location.

Wherein, the magnetic yoke is C-shaped, in fact, the shoulder chamfers on both sides of the magnetic yoke are defined so that the magnetic yoke is C-shaped as a whole. The shoulder of the magnetic yoke is chamfered, which can greatly reduce the magnetic flux leakage in this part, thereby not only reducing the magnetic loss, but also more importantly, the magnetic flux leakage will not cause a large number of other surrounding parts containing magnetic chips during high-power operation. For example, iron parts and copper wires cause serious eddy current damage.

Wherein, the spacing of the central area of the air gap is smaller than the spacing of the surrounding positions, in fact, the spacing of the surrounding positions of the air gap is increased, so that the magnetic resistance of the central area of the air gap is much smaller than the magnetic resistance of the surrounding positions. The magnetic field is brought closer to the central area to reduce magnetic flux leakage, thereby reducing the eddy current caused by the magnetic flux leakage to the surrounding copper wires; wherein the central area of the air gap and the peripheral position are smoothly connected. In order to realize this structure, various methods can be realized, such as arranging chamfering at the corners of at least one side of the upper and lower yokes or the core column. The corners at the air gap are arranged as chamfered corners, and the magnetic core surface defining the air gap is arranged as a chamfered structure. The chamfered structure can be either rounded or chamfered. Secondly, the chamfering structure is obviously not the process chamfering that usually exists due to the needs of the manufacturing process, nor is it the so-called deburring rounding, but the angle is much larger than the process chamfering or deburring rounding. rounding. The radius of this common process chamfering or deburring in product manufacturing is no greater than 0.5 mm.

According to the above structure, compared with the prior art, since the magnetic yoke is C-shaped, the magnetic flux leakage at the shoulder of the magnetic yoke can be greatly reduced, thereby reducing the magnetic loss; By increasing the spacing, the magnetic resistance of the central area of the air gap is much smaller than that of the surrounding positions, so that the magnetic field is moved closer to the central area and the magnetic flux leakage is reduced, thereby reducing the eddy current caused by the magnetic leakage to the surrounding copper wires.

A further technical solution may also be that the chamfers are rounded corners, and the radius of the rounded corners is greater than the distance between the central regions of the air gaps.

A further technical solution may also be that the chamfer is a 45° bevel, and the length of the straight side of the bevel is greater than the distance between the central regions of the air gap.

A further technical solution may also be that the upper and lower magnetic yokes are integrally formed magnetic cores, and the core column is formed by splicing a plurality of block-shaped magnetic blocks. This can further improve the applicability to high magnetic field strengths.

A further technical solution may also be that, perpendicular to the spacing direction of the three-dimensional central region of the magnetic core plane, a tapered magnetic core is formed with a gradually smaller cross section of the magnetic core approaching the air gap.

The present invention also provides an inductance device using the metal powder magnetic core combined according to any one of claims 1 to 4, characterized in that it comprises two coil windings and the combined metal powder according to any one of claims 1 to 4. A magnetic core, one of the core legs is inserted into one of the coil windings, and both ends of the upper and lower yokes are also partially inserted into the central space defined by the coil windings to allow the air gap is also enclosed in the coil winding.

In a further technical solution, the core column may be composed of two sub-columns arranged up and down.

A further technical solution may further include an outer fixing frame, and the combined metal powder magnetic core and the coil winding are compressed in the outer fixing frame.

Since the present invention has the above-mentioned features and advantages, it can be applied to the combined metal powder magnetic core and inductance device. The inductance device includes a high-current transformer, an adapter, a reactance, a charging pile PFC inductance, and the like.

Description of drawings

FIG. 1 is a schematic diagram of an inductor device to which the technical solution of the present invention is applied.

Embodiments of the present invention

The structure of the metal powder magnetic core and the inductance device using the combination of the technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings. As shown in FIG. 1 , the inductor device 100 includes a combined metal powder magnetic core and coil windings ( 21 , 22 ). The present invention first proposes a solution by modifying the shape of the magnetic core at the splicing of the magnetic circuit of the magnetic core, and provides a combined metal powder magnetic core, the combined metal powder magnetic core includes upper and lower magnetic yokes (11, 12) and The stems (13, 14) are arranged between the upper and lower yokes (11, 12). The upper and lower magnetic yokes (11, 12) are respectively C-shaped. Wherein, the yoke is C-shaped, which actually defines that the shoulders on both sides of the yoke have chamfers R2, and the chamfer R2 is preferably a large rounded structure, so that the yoke as a whole looks like a chamfer R2. Type C. The shoulder of the magnetic yoke is chamfered, which can greatly reduce the magnetic flux leakage in this part, thereby not only reducing the magnetic loss, but more importantly, the magnetic flux leakage will not cause a large number of other surrounding parts containing magnetic chips during high-power operation. For example, iron parts and copper wires cause serious eddy current damage.

Secondly, the two ends of the upper and lower magnetic yokes (11, 12) are respectively butted with the two core columns (13, 14) to form a magnetic circuit, and an air gap 3 is arranged at the butting position between them, so The spacing h1 of the central area a of the air gap 3 is much smaller than the spacing h2 of the peripheral position b; wherein the central area a of the air gap and the peripheral position b are smoothly connected. To this end, the upper and lower magnetic yokes (11, 12) and the corners of the core posts (13, 14) at the air gap 3 can all be arranged as chamfers. The maximum pitch defined by the chamfers in the up-down direction constitutes the pitch h2 of the peripheral position b. Of course, in another embodiment, a chamfer can also be set at the orientation of one side to increase the distance h2 between the peripheral positions b of the air gap 3 .

Wherein the chamfer is a rounded corner R1, and the radius of the rounded corner R1 is greater than the distance h1 of the central area of the air gap 3, preferably greater than 1.5h1; in another embodiment (not shown in the figure), The chamfer is a 45° bevel, and the length of the straight side of the bevel is greater than the distance between the central regions of the air gap 3, preferably greater than 1.5h1. Such a structure actually increases the distance between the peripheral positions of the air gap 3, so that the magnetic resistance in the central area of the air gap 3 is much smaller than the magnetic resistance in the peripheral positions, so that the magnetic field moves closer to the central area and reduces magnetic flux leakage. This further reduces the eddy current caused by the magnetic flux leakage to the surrounding copper wires. Under the same working conditions, in the area of the cross-sectional area of the coil windings (21, 22) of the present invention, the penetrated leakage magnetic flux is greatly reduced compared with the traditional square iron core solution, so the coil windings (21, 22) The high frequency Eddy current losses are also greatly reduced.

The spacing h1 of the central area of the air gap 3 refers to the spacing h1 of the central area of the air gap 3, which is not limited to the thickness above the millimeter level. Penetration effect of leakage flux on the coil surface at the splicing.

Among them, the chamfering structure is obviously not the process chamfering that usually exists due to the needs of the manufacturing process, nor is it commonly referred to as deburring and rounding, but is much larger than the angle of process chamfering or deburring and rounding. rounding. The radius of this common process chamfering or deburring in product manufacturing is no greater than 0.5 mm.

A further technical solution may also be that the upper and lower magnetic yokes (11, 12) are integrally formed magnetic cores, and the core pillars (13, 14) are formed by splicing a plurality of block-shaped magnetic blocks. This can further improve the applicability to high magnetic field strengths.

The present invention shows a rounded magnetic core in a plane direction. A further technical solution can also be that the spacing direction of the three-dimensional central area perpendicular to the plane of the magnetic core is formed to gradually reduce the cross section of the magnetic core close to the air gap 3 of tapered cores. It also has the effect of the present invention, and is also the main embodiment of the present invention.

The present invention also provides an inductance device 100 using the combined metal powder magnetic core described in any one of claims 1 to 4, comprising two coil windings (21, 22) and the combined metal powder magnetic core, one The stems (13, 14) are inserted into one of the coil windings (21, 22), and both ends of the upper and lower yokes (11, 12) are also partially inserted into the coil windings (21). , 22 ) in the central space so that the air gap 3 is also enclosed in the coil windings ( 21 , 22 ). Wherein, the core column (13, 14) can be an integral section, or can be composed of two or more sub-columns (not shown in the figure) combined up and down, so that it can be adapted to different central areas The pitch of the coil windings (21, 22).

In the present invention, the coil winding can be composed of one coil on the left and one on the left as shown in FIG. 1 , or a plurality of coils can be set in the unilateral magnetic circuit for application, as long as the air gap 3 of the magnetic core splicing is within the limit of the coil. Inside the central space of the invention, and in line with the application of the above-mentioned features, it still has the actual effect of the present invention.

A further technical solution may also include an outer fixing frame (not shown in the figure), and the combined metal powder magnetic core and the coil windings (21, 22) are compressed in the outer fixing frame. The outer fixing frame is used for positioning the combined metal powder magnetic core, and can also position the coil windings (21, 22) to prevent them from loosening.

Claims

The combined metal powder magnetic core includes upper and lower yokes and a core column arranged between the upper and lower yokes; it is characterized in that the upper and lower yokes are respectively C-shaped, and the upper and lower The two ends of the magnetic yoke are respectively butted with the two core posts to form a magnetic circuit, and an air gap is arranged at the butting position between them, and the distance between the central area of the air gap is smaller than the distance between the peripheral positions.
The combined metal powder magnetic core according to claim 1, characterized in that, at least the upper and lower magnetic yokes or the corner angular positions of one side of the core column are arranged as chamfers.
The combined metal powder magnetic core of claim 2, wherein the chamfers are rounded corners, and the radius of the rounded corners is greater than the spacing of the central region of the air gap.
The combined metal powder magnetic core of claim 2, wherein the chamfer is a 45° bevel, and the length of the straight side of the bevel is greater than the distance between the central regions of the air gap.
The combined metal powder magnetic core according to claim 1, 2, 3 or 4, wherein the upper and lower magnetic yokes are integrally formed magnetic cores, and the core column is composed of a plurality of block-shaped magnetic blocks stitched together.
The combined metal powder magnetic core according to claim 1, 2, 3 or 4, wherein the spacing direction of the three-dimensional central region perpendicular to the plane of the magnetic core forms a magnetic core cross section close to the air gap progressively smaller tapered cores.
An inductance device applying the combined metal powder magnetic core of any one of claims 1 to 6, characterized in that it comprises two coil windings and the combined metal powder magnetic core of any one of claims 1 to 6, one of which is The core column is inserted into one of the coil windings, and both ends of the upper and lower yokes are also partially inserted into the central space defined by the coil windings so that the air gap is also surrounded by the coil winding. in the coil winding.
The inductor device according to claim 7, wherein the core column is composed of two sub-columns arranged one above the other.
The inductor device according to claim 7, further comprising an outer fixing frame, and the combined metal powder magnetic core and the coil winding are compressed in the outer fixing frame.